Construction of Wuhan's ecological security pattern under the "quality-risk-requirement" framework

The ecological security pattern aims to maintain the integrity of landscape pattern and the continuity of ecological process to ensure urban ecological security. Current ecological source identification methods lack the consideration for ecological land degradation risks and human ecological needs. Taking Wuhan City as an example, the comprehensive value of ecological land was calcula-ted from three aspects, including ecological land quality, ecological degradation risk, and ecological demand to identify ecological source areas. Basic ecological resistance surfaces were constructed based on land use types and nighttime light data. Potential ecological corridors were identified based on the minimum cumulative resistance model. Ecological "pinch points" were recognized based on circuit theory. After that, we built a "four horizontal, three vertical and ten groups" ecological safety pattern in Wuhan. The results showed that the area of ecological land in Wuhan was 2138.2 km , accounting for 24.9% of the total area of the city. These areas were primarily attributed to waters and foress, clustering in the north and south of the city. The total length of ecological corridors was 1222.42 km, with 566.75 km aquatic corridors and 655.67 km land corridors. The aquatic corridors traversed the city area to form a double cross-shaped pattern. The land corridors circularly distributed around the city. Comprehensively, the "four horizontal and three vertical" spatial pattern had appeared. There were a total of 44 ecological pinch points on the ecological corridor, distributed circularly with the central city as the kernel. The extant protection space had almost been included in the identified ecological source area, supporting the ecological significance of the identification framework. It would help to provide a quantitative framework for the construction of ecological secu-rity pattern in the metropolitan area and to guide the relevant urban spatial planning.